bug#54043: closed (Simple regexp bug [contains spoiler for today's wordle])

[GNU bug Tracking System]

Your message dated Thu, 17 Feb 2022 08:13:54 -0800
with message-id 
<CA+8g5KHTHWgsARaMqS7dsL6yJCmMUP+U7ZVC5j-0qqMefOzCEQ@mail.gmail.com>
and subject line Re: bug#54043: Simple regexp bug [contains spoiler for today's 
wordle]
has caused the debbugs.gnu.org bug report #54043,
regarding Simple regexp bug [contains spoiler for today's wordle]
to be marked as done.

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54043: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=54043
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> --- Begin Message ---
>
>
>
> Subject: 
>
> Simple regexp bug [contains spoiler for today's wordle]
>
>
>
>
> Date: 
>
> Thu, 17 Feb 2022 14:47:04 +0000
>
>
>
>
> I noticed this one while doing:
>
> $ grep sha[^s]e five-letter-words
> share
>
> which doesn't fit with:
>
> $ grep sha.e five-letter-words
> shade
> shake
> shale
> shame
> shape
> share
> shave
>
> A reproducer is easy:
>
> $ echo shame |grep sha[^s]e
> (no output)
>
> Almost any change to the regex & input will make it work, even rot-13
> of both.  For example:
>
> $ echo shamel |grep sha[^s]e
> (no output, still fails)
> $ echo shamel |grep sha[^s]el
> shamel
> $ echo sshame |grep ssha[^s]e
> sshame
> $ echo funzr |grep fun[^f]r
> funzr
>
> $ grep --version
> grep (GNU grep) 3.7
> Copyright (C) 2021 Free Software Foundation, Inc.
> License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
> This is free software: you are free to change and redistribute it.
> There is NO WARRANTY, to the extent permitted by law.
>
> Written by Mike Haertel and others; see
> <https://git.sv.gnu.org/cgit/grep.git/tree/AUTHORS>.
>
> This is Debian amd64, grep package version 3.7-1.
>
>
>
> --- End Message ---
> --- Begin Message ---
>
>
>
> Subject: 
>
> Re: bug#54043: Simple regexp bug [contains spoiler for today's wordle]
>
>
>
>
> Date: 
>
> Thu, 17 Feb 2022 08:13:54 -0800
>
>
>
>
> On Thu, Feb 17, 2022 at 7:46 AM Matthew Wilcox <willy@infradead.org> wrote:
> > I noticed this one while doing:
> >
> > $ grep sha[^s]e five-letter-words
> > share
> >
> > which doesn't fit with:
> >
> > $ grep sha.e five-letter-words
> > shade
> > shake
> > shale
> > shame
> > shape
> > share
> > shave
> >
> > A reproducer is easy:
> >
> > $ echo shame |grep sha[^s]e
> > (no output)
>
> This is not a bug in grep. Your failure to quote the regular expression
> means that the argument is first interpreted by the shell.
> To demonstrate the argument that "grep" ends up using,
> run this from that same directory:
>
>   echo sha[^s]e
>
> If I have something named e.g., "shape" in the current directory, that
> would print "shape". If I have two matching names, e.g., shave and shale,
> it will print both names.
>
> IMHO, it is almost always best to single-quote regular expressions like that.
> Quoting your reproducer, you see it works as desired:
>
>   $ echo shame |grep 'sha[^s]e'
>   shame
>
>
> --- End Message ---